Radeon HD 5870 vs Radeon HD 7850

Intro

Compare that to the Radeon HD 7850, which uses a 28 nm design. AMD has clocked the core frequency at 860 MHz. The GDDR5 RAM runs at a frequency of 1200 MHz on this particular model. It features 1024 SPUs as well as 64 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7850		130 Watts
Radeon HD 5870		188 Watts
	Difference: 58 Watts (45%)

Memory Bandwidth

Both cards have exactly the same memory bandwidth, so theoretically they should have the same performance. (explain)

Texel Rate

The Radeon HD 5870 will be quite a bit (approximately 24%) faster with regards to texture filtering than the Radeon HD 7850. (explain)

Radeon HD 5870		68000 Mtexels/sec
Radeon HD 7850		55040 Mtexels/sec
	Difference: 12960 (24%)

Pixel Rate

The Radeon HD 7850 will be a little bit (more or less 1%) better at full screen anti-aliasing than the Radeon HD 5870, and capable of handling higher resolutions while still performing well. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 5870		27200 Mpixels/sec
	Difference: 320 (1%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of data (counted in megabytes per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.